CD 



THE PROCESS OF RIPENING IN THE TOMATO, 

CONSIDERED ESPECIALLY FROM THE 

COMMERCIAL STANDPOINT. 



CHARLES E. SANDO. 



A Dissertation Submitted in Partial Fulfillment op the Require- 
ments for the Degree of Doctor of Philosophy in the 
Maryland State College of Agriculture. 






nlCf 



UNITED STATES DEPARTMENT OF AGRICULTURE 







BULLETIN No. 859 

Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 




J^f^LTU 



Washington, D. C. 



September 7, 1920 



THE PROCESS OF RIPENING IN THE TOMATO, CON- 
SIDERED ESPECIALLY FROM THE COMMERCIAL 
STANDPOINT. 1 

By Charles E. Sando, 
formerly Junior Chemist, Horticultural and Pomological Investigations. 



CONTENTS. 



Pago. 
Shipments of early tomatoes to northern 

markets 1 

Growing and handling tomatoes in the field . . 3 

Packing and shipping operations 4 

Previous chemical investigations of the 

tomato 7 

Experimental material 13 

Methods of analysis 15 

Analytical data concerning progressive 

changes in composition during ripening.. 17 



Page. 



Comparison of the composition of commer- 
cially picked tomatoes with turning and 

vine-ripened fruit 21 

Effect of lack of ventilation on ripening 24 

Summary and conclusions 30 

Literature cited 32 

Appendix.— Comparison of the composition 
of "puffy" and normal Livingston Globe 
tomatoes 37 



SHIPMENTS OF EARLY TOMATOES TO NORTHERN MARKETS. 

The shipping of tomatoes grown in Florida to northern markets 
during the winter and spring months is an exceedingly important 
industry. In Table I are presented statistics prepared by the 
Bureau of Crop Estimates and the Bureau of Markets of the United 
States Department of Agriculture, showing the production and 
car-lot shipments of the seven States where the early-tomato crop 
is chiefly grown. 

From the figures shown in Table I it can be seen that Florida 
ships annually more than half of the total quantity of early tomatoes 
forwarded from the seven States specified. Statistics show that 

1 This bulletin gives the results of a portion of the work carried on under the project "Factors affecting 
the storage life of vegetables". The paper was completed after the writer was transferred to the Office 
of Drug-Plant, Poisonous-Plant, Physiological, and Fermentation Investigations of the Bureau of 1'lant 
Industry. 

The writer wishes to express his special indebtedness to Mr. Thomas J. Peters, of Miami, Fla., for pro" 
viding facilities for the field work and for cooperating in other ways. He desires also to express his thanks 
and appreciation to Mr. H. H. Bartlett, of the botanical department of the University of Michigan, for 
counsel and suggestions during the progress of the work. 
175085°— 20— Bull. 859 1 



2 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

the industry in Florida is very largely concentrated in Dade and 
Broward Counties, at the southern tip of the State. 

Table I. — Production of early tomatoes in the principal producing States of the United 
States, showing also car-lot shipments, for the 5-year period from 1915 to 1919, in- 
clusive. 



State. 


Crop production (tons). 


Car-lot shipments.a 


1919 


1918 


1917 


1916 


1915 


1919 


1918 


1917 


1916 


1915 




17,380 
58, 520 


11,880 
46, 800 
600 
21,150 
10,500 
16, 000 
69, 108 


17,390 
77, 480 
1,810 
15,680 
13,020 
16, 430 
75, 540 


20, 170 
101, 170 
2,209 
25,250 
29, 320 
10,770 
85, 285 


18, 750 
91,390 
2,524 
20, 100 
24,010 
11,260 
62,212 


139 

4,478 

2 

61,388 

366 

1,198 


1,513 

3,695 

10 

61,379 

654 

1,123 

97 


518 

4,493 

14 

61,063 

947 

1,276 

173 


1,169 

6,184 

58 

61, 663 

590 

1,153 

192 


871 


Florida 


4,692 




58 




18, 400 
6,000 
17, 700 


61,690 




529 


Texas 


1,318 




121 








Total 


118,000 


176,038 


217, 350 


274, 174 


230,246 


7,571 


8,471 


8,484 


11,009 


9,279 







a Estimated at 13 tons per car except in Mississippi, where the average is 10| tons per car. 
6 Carloads of 10J tons. 

In spite of the fact that thousands of cars of Florida tomatoes 
are shipped to the North each year, the quality of a large percentage 
that reaches the consumer is admittedly inferior in many respects 
to vine-ripened or greenhouse tomatoes. Tracy (52) * makes the 
following statements in regard to the inferiority of shipped fruit: 

The tomato never acquires its full and most perfect flavor except when ripened on 
the vine and in full sunlight. Vine and sun ripened tomatoes, like tree-ripened 
peaches, are vastly better flavored than those artificially ripened. This is the chief 
reason why tomatoes grown in hothouses in the vicinity are so much superior to 
those shipped in from farther south. 

It is the custom to pick the fruit when grass green and allow it 
to ripen and color in ripening rooms before shipment, while in 
transit, and after arrival at the market. Numerous complaints 
have been made by commission men and others that a large pro- 
portion of the tomato crop from the east coast of Florida is picked 
and shipped too green. When this is done, the fruit ripens very 
slowly, has a tendency to wrinkle, colors abnormally, and has a bad 
taste and flavor. Moreover, for quite different reasons, the growers 
prefer, when shipping their tomatoes, to have the fruit arrive in a 
slightly colored condition. The arrival of green fruit at the terminal 
often has the effect of glutting the market. The buyer is compelled 
to hold the fruit while ripening and consequently assumes a risk 
of losing a portion, whereas if the shipment is colored when it 
arrives he is able to dispose of it immediately. 

Since the difficulties just enumerated bear a close relationship 
to field practice and to packing and shipping operations, the writer 
was stationed at Miami during the growing seasons from 1917 to 
1919 in order to gain first-hand knowledge of the industry and to 

1 The serial numbers in parentheses refer to "Literature cited" at the end of this bulletin. 



> D 









PROCESS OF RIPENING IN THE TOMATO. 6 

conduct experimental work with material grown under the con- 
ditions peculiar to Florida. 

The quality of a tomato is largely determined by the amount and 
kind of sugars, plant acids, and vitamins which are present. It was 
obvious, therefore, that the method of approaching the problem would 
be a chemical one. If the chemical composition of vine-ripened toma- 
toes were known for a number of stages in the process of ripening, 
the data would afford a criterion for judging commercially ripened 

fruit. 

GROWING AND HANDLING TOMATOES IN THE FIELD. 

In the region about Miami, Fla., the seed beds are prepared as 
early as the middle of September and are planted at intervals until 
the early part of February in order to insure a steady supply of seed- 
lings. In transplanting seedlings they are placed full length in the 
furrow, the roots are covered with a handful of moist well-rotted 
stable manure, and finally the whole stem, but not the leaves, is cov- 
ered with loose soil. Commercial fertilizer is often used with the 
manure. 

The soil upon which tomatoes are grown is essentially of an ever- 
glade type and is. covered with water during a portion of the summer. 
For the past few years the moist soil and the danger of frost have 
been serious handicaps to very early planting. To insure a crop of 
tomatoes in case of frost many growers plant a portion of their 
fields in hills. The seeds are planted over stable manure and com- 
mercial fertilizer. After the seedlings appear the hills are thinned to 
one plant, which is allowed to grow to 6 inches or more in height and 
then bent down and covered with soil. The plants are 2 to 3 feet apart 
in rows 6 feet apart. 

Commercial fertilizers are applied throughout the growing season 
up to picking time. Where only one side of the row is cultivated 
and the other allowed to grow in weeds, upon which the plants later 
lean, the fertilizer is applied hi furrows on the side which is cultivated. 
About a week or 10 days after the plants are set out a small handful 
of the fertilizer is placed on one side of each plant. Sometimes it 
is covered with soil, but generally it is left uncovered. Ten days or 
two weeks after the first application, more fertilizer is applied be- 
tween the plants hi the original planting furrow. A shallow furrow 
is then turned to cover this fertilizer and also to support the plants 
better. The third application is placed hi the furrow made when 
the second application was covered. The quantity is generally 
larger than the first and second applications and is covered by a 
new furrow. The fourth and final application is made in the same 
way. Where the fertilizer is applied at one side only, two rows are 
planted close together and between them weeds are allowed to 
grow. Where fertilizer is applied to both sides of the plants the 



4 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

• 

rows are 6 feet apart. The procedure is the same. The usual 
practice is to fertilize at the rate of 1 to 1^ tons per acre, the last 
application being made several weeks before picking. The interval 
between applications varies with weather conditions and the growth 
of the plants. The custom is to locate the position of the rootlets 
along the side of the furrow made at the preceding application and 
to keep a quantity of fertilizer just ahead of these rootlets, so that a 
constant supply is available for the plant. 

The time of picking the tomatoes of course depends upon the age 
and condition of the fruit. Many growers believe that it is an easy 
matter to determine the maturity by the character of the darkened 
area around the stem end. Toward the last stages of maturation 
the chlorophyll gradually disappears, especially around the stem end, 




Fig. 1.— A tomato fipld in Florida. 

where a whitened area is left. Fields are gone over once a week by the 
pickers, who collect the fruit in baskets or tin buckets. (Fig. 1.) 
In general the pickers (Nassau negroes) do not pay much attention 
to the color of the tomatoes, but gather those that appear large 
enough to ship. The tomatoes are dumped into field boxes at the 
ends of the rows and carried by wagon to the ripening house or pack- 
ing house. The fruit is generally handled carefully, but often it is 
dropped from the gathering bucket to the field crate without the 
picker even bending over. 

PACKING AND SHIPPING OPERATIONS. 

Until recently the fruit was sorted, packed, and shipped imme- 
diately upon its arrival at the packing house, but the loss through 
disease and bruising was so great that it became necessary to adopt 



PROCESS OF- RIPENING IN THE TOMATO. 5 

the ripening house as a means of culling out undesirable fruit be- 
fore shipping. In the ripening house the fruit is stored at a tem- 
perature of 75° to 85° F. for a variable period, depending upon the 
uniformity and maturity of the tomatoes at the time of picking. 
When most of them show a very slight red coloration they are re- 
moved and carefully sorted; all diseased fruits are discarded and the 
colored, ones are graded, wrapped, and packed for shipment. Green 
fruit goes back to the ripening room. Improper conditions of ven- 
tilation, humidity, and temperature in the ripening room often 
increase the amount of disease, since such conditions favor the ger- 
mination of fungous spores and the spread of infections brought 
from the field. Nevertheless, this method of allowing diseases to 
develop and then culling the fruit before shipping saves paying 
transportation charges on spoiled fruit, as well as additional' loss in 
transit through the spreading of infection to healthy fruit. 

The use of the ripening room is restricted to the early months of 
shipping, when the weather conditions are such as to allow the fruit 
to be shipped in a colored condition. The temperature is generally 
low enough to prevent too rapid ripening, and when the fruit reaches 
the North the temperature is still colder, thus allowing the fruit to be 
kept for a considerable length of time before it becomes too ripe. La- 
ter in the season, however, it is inadvisable with the present methods 
of handling to ship colored fruit. The tomatoes are kept in the 
ripening room for two or three days, to allow infections to develop, 
and are then sorted and shipped. In general, after warmer weather 
sets in the green fruit goes directly to the packing house from the 
field and is graded and shipped at once. Sometimes it ripens in 
transit, but more often it arrives green and has to be ripened at the 
terminal. Frequently the fruit is packed in such an immature state 
that it never attains its normal color. In such instances the grower 
loses both in reputation and in financial return. 

When the tomatoes arrive at the packing shed they are dumped 
into bins, which usually are large enough to hold several crates. 
From these bins the grader culls all undesirable fruit and throws the 
good fruit into other bins, assorting according to size. Packers stand- 
ing directly in front of the bins wrap the fruits individually in special 
tomato paper and pack them in 4-quart baskets. Each basket re- 
quires smaller fruit at the bottom layer than at the top, where 
the basket is wider, but in every basket the fruit is packed very 
tightly; in some cases quite a little squeezing is necessary. Six 
baskets are placed in each crate. The top is considerably bulged, 
owing to the close packing of the baskets. Crates in various stages 
of packing are shown in figure 2. 

The method of packing crates for shipment just described is un- 
fortunately the one generally used at the present time, but there is 



6 



BULLETIN 859, IT. S. DEPARTMENT OF AGRICULTURE. 



another method that deserves careful consideration, in which the 
fruit after it is picked is washed and handled by means of a machine. 

The field crates used in connection with the machine, and also by 
many growers who do not use a machine, are made of hardwood 
mill edgings that have been carefully planed and smoothed, especially 
where the tomato is likely to come in contact with them. The crate 
is open, so that all sand and dirt fall through and do not injure the 
tomatoes during hauling. 

When the tomatoes arrive at the packing shed they are dumped 
into a large tank at the end of the machine, which contains a special 
washing solution kept at as high a temperature as the fruit will stand. 




Fig. 2.— Scene in a Florida tomato packing house. 

Were the solution with which the tomatoes are washed nothing more 
than hot water, it can hardly be doubted that the thorough removal 
of adhering sand, dirt, and fungous spores would be beneficial. The 
tomatoes remain in this supposedly disinfectant solution for about 
half a minute, constantly revolving, and are pushed toward an end- 
less chain which carries them up an incline, where a spray of cold 
water rinses off the washing mixture. Drying is accomplished by 
passing the fruit between two layers of sponges. As it passes over 
the rollers, cullers are able to pick out the undesirable fruit without 
handling the remainder. It then passes over a special sizer, from 
which the several grades drop on tightly spread duck inclined planes 



PROCESS OF RIPENING IN THE TOMATO. 7 

and roll down into pockets. The tomatoes are not jarred or bruised 
in any way in traveling from the tank to the packer. 

Careful handling is essential in the successful production and ship- 
ping of tomatoes, and machine handling in the packing house is 
therefore to be highly recommended. Any device which will prevent 
bruising and cutting will reduce the opportunities for fungous infec- 
tion and subsequent loss. 

Refrigerator cars without ice are preferred by the growers for ship- 
ping, since these cars are fitted with ventilators which can be opened 
and closed as weather conditions require. Ventilated cars are used 
also when there is a shortage of refrigerator cars, but owing to their 
poor construction there is likelihood in the colder regions of the fruit 
freezing. When the cars first leave the South the custom is to have 
the ventilators open, but as they move farther north these are closed 
to prevent frost injury. When the cars are billed through to Canada 
some shippers close the ventilators as soon as the cars are filled. 
Each car contains an average of 500 crates, or approximately 13 tons 
of fruit. With so large a volume of respiring fruit in a confined space 
it is obvious that a condition of oxygen deficiency may easily come 
about. 

PREVIOUS CHEMICAL INVESTIGATIONS OF THE TOMATO. 

The earliest important chemical investigations of the tomato seem 
to have been those of J. F. John and C. Bertagnini, cited by Peckolt 
(37, p. 197). The latter author states that John probably made the 
first analysis of the tomato in 1814. Bertagnini, according to Pal- 
meri (34), isolated citric acid from this fruit in 1850 and identified 
it by means of its silver salt. 

In 1873, Kennedy (27) first isolated the alkaloid solanin from the 
tomato. His method was to macerate with dilute sulphuric acid 
for 48 hours. The expressed liquid was then treated with aqueous 
ammonia (sp. gr., 0.96) in excess. The precipitate which separated 
was filtered and dried at 120° F., after which it was extracted with 
hot alcohol. On cooling, the alcoholic solution deposited solanin as 
small feathery crystals. 

The first quantitative analysis of the whole tomato fruit was that 
of Dahlen (16), who reported the amounts of water, protein, fat, 
glucose, crude fiber, ash, nitrogen, and phosphoric acid. 

Since the work of Dahlen, various chemists have published analyses 
of the tomato. Palmeri (34) in 1885 reported on the constituents of 
various portions of the fruit and also included an ash analysis. 
Various later attempts were made to show the amounts of nitrogen, 
phosphoric acid, and potash which the tomato removed from the 
soil and also the effect of different fertilizer treatments on the com- 
position of the fruit. The most important work along this line was 



8 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

performed by Patterson (36), Bishop and Patterson (12), Voorhees 
(55), Alwood (3), Alwood and Bowman (4), Bailey and Lodeman (8), 
Bailey (7), and Jenkins and Britton (26). 

There has been no little difference of opinion concerning the kind 
of acid occurring in the tomato. As before stated, Bertagnini (37) 
isolated and identified the acid as citric, while McElhenie (30) be- 
lieved that oxalic, citric, and malic acids were present. Patterson 
(36) makes the following statement: 

On following the schemes for the detection of organic acids as given in Fresenius's 
Qualitative Analysis, paragraph 193, page 342, and Prescott's Organic Analysis, page 
336, the following acids were found to be present in the concentrated juice of the 
tomato, viz, malic, tartaric, benzoic, and formic. Malic acid predominated and the 
others appeared to be present in very small quantities, and as there has been no time 
for a further investigation as to the relative amounts of these, the whole of the free 
acids has been calculated as malic acid. 

Passerini (35) claims that the acidity is due chiefly to citric acid 
and makes the statement : 1 

II sapore dolce e dovuto a glucosi, i quali hanno azione resultante levogira sulla 
lucepolarizzata; l'aciditaper la massima parte ad acido citrico, come dimostrammo 
in altra nota. 

Briosi and Gigli (13) also confirm the presence of citric acid: 2 
Queste esperienze provano nel liquido giallo la presenza dell'acido citrico; e siccome 
isaggi con l'acqua di calce e col cloruro di calcio, ed altri che per brevita non rife- 
riamo, escludono l'acido tartarico, possimao credere che l'acidita stessa sia, almeno 
per la massima parte dovuta a esso acido citrico, gia riconosciuto nel pomodoro per la 
prima volta da Bertagnini. 

Alwood and Bowman (4) make the following statement: 
A qualitative examination showed the presence of citric, malic, tartaric, formic, 
and succinic acids. Of these the citric acid was by far the most abundant, so that in 
the quantitative determinations the whole acid was calculated as citric acid. 

Stliber (50) reports that apparently all the acid present was citric, 
and in no case was tartaric, malic, or succinic acid found. 

Formenti and Scipiotti (19) claim that salicylic acid occurs 
naturally in the tomato to the extent of 15 to 25 milligrams per kilo- 
gram of fresh fruit juice. 

Albahary (1) gives the following acids as occurring in the tomato: 
Malic, 0.48 per cent; citric, 0.09 per cent; oxalic, 0.001 per cent; 
tartaric and succinic, traces. He also reports the presence of an 
amino acid (2). 

Bacon and Dunbar (6) state that — 
the acid of tomatoes has been called by various authors malic, citric, tartaric, and 
oxalic. The acid is actually citric, as shown. * * * 

1 Translated as follows: The sweet taste is due to glucose, which has a resulting levorotatory action upon 
polarized light; the greatest part of the acidity is due to citric acid, as we have shown in a previous note. 

2 Translated as follows: These experiments prove the presence of citric acid in the yellow liquid; experi- 
ments with lime water and calcium chlorid and others which we do not mention tor the sake of brevity 
exclude tartaric acid. We may believe that this same acidity is due, at least for the most part, to that 
citric acid already recognized in the tomato for the firsl time by Hertagnini. 



PROCESS OF RIPENING IN THE TOMATO. 9 

Congdon (15) differs from Bacon and Dunbar (6) and claims that 
the acids are oxalic, citric, and a very slight amount of malic. 
Oxalic acid is supposed to predominate. 

The preponderance of opinion seems to be that the chief acid in 
the tomato is citric. 

With regard to the kind of sugar occurring in the tomato there is 
more uniformity of opinion. Patterson (36) says: 

A few samples of tomatoes were examined for both classes of sugars, the glucose 
being determined in solutions made up without application of heat; and then a por- 
tion of this solution was made up in the usual manner for the cane-sugar determina- 
tions. The amount of increase indicating cane sugar was so small that it was thought 
to be probably due to substances of a gummy or pectose nature, which are well under- 
stood to form sugars which act on Fehling's solution when treated with mineral acids. 
And from the amount of free acid in the tomato, cane sugar would not be likely to 
exist to any extent. 

Briosi and Gigli (13) believe that levulose is the sugar to which the 
sweetness of the yellow juice is chiefly due. 

Alwood and Bowman (4) say that "it is very probable that no 
other sugars than those of the glucose kind exist in tomatoes." . 

Snyder (46), however, reports the presence of reducing and non- 
reducing sugars. 

Stiiber (50) finds no change in the sugar content of sugar samples 
before and after inversion. 

Albahary (2) presents data showing the presence of cane sugar. 

Bacon and Dunbar (6) make the following statement: 

A number of experiments have shown that the sugar of tomatoes is usually invert 
sugar, with at times a slight excess of levulose. 

Thompson and Whittier (51) were unable to find sucrose in either 
green or ripe fruits, but reported approximately equal quantities of 
levulose and dextrose, concluding that in the classification of fruits 
according to the kind of sugar present the tomato falls in the invert- 
sugar group. One of the more recent investigators, Bigelow (11), 
shows that sucrose is probably absent. He states : 

It is probable that the sugar in tomatoes is all invert sugar. This was indicated by 
some samples which were examined, in which the determination of sugar before and 
after inversion gave the same results. 

The work herein reported supports the contention of most scientific 
workers that little or no cane sugar is present in the tomato. It is 
very probable that where small amounts of sucrose are indicated bv 
the increased reduction of Fehling's solution after acid hydrolysis 
that the increased reduction is due to other substances than invert 
sugar. 

Since the data of the present investigation concern the percentage 
composition of the entire fruit, the comparable results of previous 
analyses of the whole tomato have been assembled in Table II. 
175085°— 20— Bull. 859 2 



10 



BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 



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PROCESS OF RIPENING IN THE TOMATO. 



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12 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

Relatively few investigations have been reported showing the pro- 
gressive changes in composition of the tomato. Differences in com- 
position between green and ripe fruit are given in several instances, 
but the researches of Albahary (2) and Bigelow (11) seem to be the 
only systematic studies of the changes occurring during development. 

Passerini (35) reports a partial analysis of both green and ripe 
fruits of two varieties. The data, which are expressed in terms of wet 
weight, seem to indicate that as the tomato matures there is an in- 
crease in water and sugar and a decrease in total solids and acid. 
Formenti and Scipiotti (19) found that the water content of the entire 
fruit was greater in the ripe fruit than in that half ripe. Thompson 
and Whittier (51) reported a slightly larger percentage of total 
sugar in ripe than in green tomatoes. 

Congdon (15) reported the specific gravity of ripe and green 
tomatoes as 1.0216 (average of eight) and 1.0230, respectively; also 
the citric acid content as 0.528 (average of eight) for ripe and 0.990 
for green fruit. Bigelow (11) studied the composition of tomatoes 
(expressed juice) at different stages of maturity, but did not arrive 
at any very definite conclusions. He states that in general the per- 
centage of solids and sugars increases and the percentage of acid 
decreases as the tomato becomes more mature. 

Albahary (2) has given the most complete account of the chemical 
transformations in tomatoes during ripening. He used three succes- 
sive stages of ripening: (1) Green fruit before seed development, 
(2) green fruit at the time seeds were completely formed, and (3) 
fruit which was fully ripe, and he concluded that with ripening there 
is a progressive increase in acids, sugars, starch, and nitrogenous 
nonprotein constituents, while proteins and cellulose diminish greatly, 
remaining practically stationary toward the end of ripening. 

From the preceding resume of former work on the chemical com- 
position of the tomato at different stages of its growth, it is seen that 
there is little consistency in the results obtained. 

The red pigment of the tomato is not estimated in any of the 
routine analyses. It has been isolated by several workers, who found 
that the amount recoverable was 0.2 per cent of the dry weight of 
the fruit or less. Its preparation in pure crystalline condition was 
first accomplished in 1876 by Millardet (31), who named it solanoru- 
bin. After it had passed into the synonymy of carotin, it was again 
isolated, in 1903, by Schunck (45), who renamed it lycopin. Mon- 
tanari (32) made the first analysis and proved that it was a hydro- 
carbon. The final identification of lycopin as an isomer of carotin 
was made by Willstatter and Escher (58). In 1913 Duggar (17) 
studied the effect of conditions upon the development of the tomato 
pigmentation and found the color of the ripe fruit to depend (1) 
upon the presence or absence of lycopin in the flesh (in the absence 
of red lycopin the flesh is yellow, due to carotin and possibly xantho- 



PROCESS OF RIPENING IN THE TOMATO. 13 

phyll, which are masked in the red fruit) and (2) upon the presence 
or absence in the epidermal walls of a yellow pigment. In the pres- 
ence of the latter the red flesh is seen through a yellow screen, giving 
a more or less orange effect, but if it is absent the skin is transparent 
and the color a clear red. 

EXPERIMENTAL MATERIAL. 

The fruit for all the analytical work herein reported (with the 
exception of the "puffy" fruit discussed in the appendix) was obtained 
from plants of the Livingston Globe variety grown at Peters, Dade 
County, Fla. This variety is almost exclusively used for winter 
shipping to northern markets. For the life-history work the plants 
were grown in a field where the soil conditions represented the average 
of the entire acreage planted in tomatoes. These plants had the same 
treatment as the commercial plantings. They were set in the field 
in January and, following the local practice, were given four applica- 
tions of commercial fertilizer and the usual quantities of compost. 

In the former studies of the progressive changes in composition 
during ripening the tomatoes for sampling were classified by size 
and were usually picked at one time. This method of sampling was 
not deemed sufficiently accurate to be used in the present investiga- 
tion, for ripe tomatoes have a great range of variation in size, which 
fact alone should enable one to conclude that it is not the size that 
determines the degree of maturity. In order to establish a basis for 
selecting fruits of comparable maturity, blossoms were tagged and 
observations made as to the time of ripening. In a series of obser- 
vations made during the summer of 1918 at Arlington, Va., several 
hundred blossoms of Livingston Globe plants were tagged, and part 
of the fruit was picked every week, weighed, and measured. The 
important fact brought out by the experiment (Table III, Sec. A) is 
that the maturity of a tomato fruit depends upon age and not upon 
size. In the latitude of Washington, D. C. (at Arlington, Va.), 
49 days were required to bring the fruit to maturity, starting with 
the blossom. Of the 20 fruits left upon the vines, all colored at the 
same time regardless of size or weight. The experiment was repeated 
with plants grown in Florida, and the same results were obtained. 
(Table III, Sec. B). In this case 200 tomatoes remained on the 
vines at the end of 56 days, 181 of which were colored (turning to red) 
and 19 green. The variations in size and weight were as great as at 
Arlington, if not greater. It was impossible to judge to the day the 
age of the blossoms which were tagged, but the variation among 
blossoms was hardly more than one or two days. 

This method of obtaining tomatoes of known relative maturity is 
a fairly accurate procedure and is certainly to be preferred to that 
used by other investigators, who selected fruit according to size. 



14 



BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 



Table III. — Weights and equatorial diameters of individual tomatoes grown at Arlington, 
Va., in the summer of 1918, and at Peters, Fla., in the winter of 1918, picked at intervals 
from blossoming time until the fruits were ripe. 



Locality and 


Color of 
fruit. 


Individual tomatoes. 


Aver- 


descriptive data. 


No. 1. 


No. 2. 


No. 3. 


No. 4. 


No. 5. 


No. 6. 


No. 7. 


No. 8. 


No. 9. 


No. 10 


age. 


Sec. A. — Arlington, Va.: 
Weight (grams) — 

Age 7 days 

Age 13 days 

Age 21 days 

Age 30 days 

Age 38 days 

Age 49 days 

Diameter (cm.) — 

Age 7 days 

Age 13 days 

Age 21 days 

Age 30 days 

Age 38 days 

Age 49 days 

Sec. B — Peters, Fla.: 
Weight (grams)— 

Age 15 days .... 

Age 21 days 

Age 28 days 

Age 35 days 

Age 42 days 

Age 56 days 

Diameter (cm.) — 

Age 7 days 

Age 15 days 

Age 21 days 

Age 28 days 

Age 35 days 

Age 42 days 

Age56days 


Green... 
...do.... 
...do.... 
...do.... 
...do;... 

Turning 
1 o red . 

Green... 

...do 

...do 

...do.... 
...do.... 

Turning 
to red. 

Green... 
...do.... 
...do.... 
...do.... 
...do.... 
...do.... 

Turning 
to red . 

Green... 
...do.... 
...do.... 
...do.... 
...do.... 
...do 

Turning 
to red 


0.30 
1.40 
39.60 
52.90 
34.30 
55.80 

.45 
1.00 
3.80 
4.20 
3.80 
4.60 

.07 
1.68 
40. 78 
43.79 
53.32 
78. 60 
79.18 

.43 
1.60 
4.50 
4.50 
4.45 
5.00 
5.25 


0.50 
2.00 
40.70 
57.10 
49.40 
94.10 

.60 
1.20 
3.80 
4.30 
4.10 
4.90 

.08 
1.75 

44.67 
62.60 
64.37 
95.45 
110. IS 

.45 
1.60 
4.55 
5.00 
4.70 
5.45 
5.65 


0.70 
3.60 
42.20 
71. 50 
64.40 
98.80 

.65 
1.60 
3.90 
4.60 
4.40 
5.20 

.08 
1.84 
45.12 
63.53 
73.40 
95.82 
127. 72 

.45 
1.60 
4.60 
5.00 
4.75 
5.50 
5.70 


0.90 
5.30 
45.00 
79.80 
76.50 
122. 80 

.80 
1.80 
4.00 
4.70 
4.80 
5.40 

.08 
2.27 
46.57 
67.12 
76.31 
99.81 
131.52 

.45 
1.70 
4.60 
5.05 
5.15 
5.60 
5.80 


1.50 
6.10 
50.50 
83.40 
81.90 
137. 20 

1.05 
1.80 
4.10 
4.80 
4.90 
5.70 

.09 
2.32 
46.67 
69.18 
94.92 
100. 78 
139. 97 

.45 
1.75 
4.65 
5.20 
5.45 
5.75 
5.90 


1.60 
13.90 
82.60 
109. 50 
155. 10 
164.00 

1.10 
2.60 
4.80 
5.40 
6.00 
5.90 

.11 

9.40 
57.03 
75.35 
95.25 
126. 66 
157. 42 

.55 
2.80 
4.85 
5.50 
5.45 
6.25 
6.40 


1.70 
14.60 
85.70 
114.30 
169.90 
180. 70 

1.15 
2.70 
4.90 
5.40 
6.10 
6.30 

.52 
10.63 
68.02 
77.48 
97.92 
151. 23 
170. 54 

.85 
2.85 
5.65 
5.50 
5.60 
7.25 
6.60 


1.80 3.00 3.40 1.54 
17.50 20.80 21.60, 10.68 
87.60 90.00 93.60 65.75 
115.70128.60 135.40 94.82 
190. 30 276. 70 2S4. 00 135. 25 
197. 60 234. 50 247. 90 153. 34 

1.15 1.40 1.55 1.14 
2.70 2.70 2.80 2.10 
4.90 4.90 5.00 4.41 
5.50 5.60 5.70 5.02 
6.40 6.70 7.30 5.45 
6.70 6.90 7.30 5.49 

.55 .67 1.13 .33 
11.95 12.39 13.19 6.74 
86.35 86.42jl24.72 63.65 
91.85 111. 97 160. 84 82.37 
100.12 118.95177.48 95.10 
195.36 222.11313.33 147.91 
179. 69 185. IS 346. 79 162. 81 

.95 1.05 1.30 .69 
2.90 3.10 3.25 2.31 
5.80 6.00 6..60 5.18 
5.80 6.20 7.00 5.47 
6.05 6.15 7.00 5.47 
7.25 7.25 7.35 6.37 
6.75 6.85 8.85 6.38 



Plates I and II show in color four stages in ripening, which are 
referred to later in this bulletin as green, i.e., with no red present (A) ; 
turning, i.e., mostly green, with a trace of color at the style end (B); 
pink, i. e., slightly colored over most of the fruit, with little or no 
green except at the stem end, but not yet a good full red (C); and 
red ripe, i. e., completely mature as far as color change is concerned (D). 

Material for analysis was obtained by tagging blossoms (other than 
those of the " crown hand") 3 soon after opening and then collecting 
tomatoes at the different stages in numbers large enough for sampling. 
An attempt was made to pick all the tagged fruit from an entire row 
in order to eliminate the error that possibly otherwise might have 
occurred of unconsciously selecting large or small fruit. Samples 
were taken at the end of the second, third, fourth, fifth, and sixth 
weeks, and after the tomatoes had barely started to color (designated 
as turning), and finally when fully colored or ripe. At the time of 
carrying on the work the weather conditions were such that eight 
weeks were required to bring the tomato to maturity (red ripeness). 



3 Growers are accustomed to refer to all the fruit developing from a single inflorescence as a "hand. 
The "crown hand" is the lowest inflorescence on the stem. It frequently fails to set fruit. 



Bui. 859, U. S. Dept. of Agriculture 



Plate I 




^ 




Color Stages in the Ripening of the Tomato. 

A : turoii 



Bui. 859. U. S. Dept. of Agriculture 



Plate II 




C 




D 






Color Stages in the Ripening of the Tomato. 

Pink, C: red ripi 



PROCESS OF RIPENING IN THE TOMATO. 15 

METHODS OF ANALYSIS. 

Sampling and preservation. — In order to obtain representative 
samples at each stage of ripening and to avoid the necessity of 
analyzing a large number of individual fruits to determine existing 
variations, composite samples were resorted to. These composite sam- 
ples were taken from approximately 20 tomatoes. To eliminate error 
due to possible correlations between size and chemical composition, 
' tomatoes were chosen sothateach composite sample was obtained from 
fruits of all sizes, with the exception of abnormally large or small 
fruit which were discarded. The method of collecting the samples 
was uniform throughout. Where the fruits were small (e. g., those 
14 days old) a 200-gram lot was made by using entire tomatoes, but 
with larger fruit samples of 200 grams were made up by removing a 
cylinder from each tomato with a half-inch cork borer. The cylinders 
were taken through the equator perpendicularly to the axis. A fairly 
representative sample was obtained in this manner, for the portion 
removed from each tomato was roughly proportional to the size of 
the whole fruit. The method of preserving samples for analysis was 
similar to that used by Hasselbring and Hawkins (21) in their studies 
of sweet potatoes and identical with the procedure of Kraus and 
Kraybill (28) with tomatoes. The material was heated with 80 per 
cent alcohol for 1 hour at 70° to 75° C, with the addition of cal- 
cium carbonate (CaC0 3 )" to insure the neutralization of acids. • Two- 
quart glass-top jars were used, and approximately 1,065 c. c. of 95 
per cent alcohol and 0.5 gram of precipitated CaC0 3 were added, 
after which the heating was carried out on a boiling water bath. 
Moisture and ash samples were merely covered with 95 per cent 
alcohol without subsequent heating. 

In preparing the samples for analysis (with the exception of certain 
moisture, dry-weight, and ash samples) the alcohol was removed from 
the insoluble residue by filtering into a 2-liter volumetric flask. The 
residue was thoroughly extracted with warm 80 per cent alcohol, 
which was cooled, filtered, and added to the original filtrate. The 
volume of the flask was then made up to mark at 20° C. (referred 
to later as the original extract) and one-tenth and three-twentieths 
aliquots pipetted off and placed in separate Florence flasks, which 
were stoppered, labeled, and set aside. The residue was dried at 
80° C. in an air oven for a few days and then allowed to come to 
air-dry weight, after which it was weighed and finely ground in a 
drug mill (referred to later as the original residue) . One-tenth and 
three-twentieths portions were weighed and stored in small stop- 
pered vials. 

Moisture, dry weight, and ash. — An entire 200-gram sample covered 
with 95 per cent alcohol was placed in a large beaker and evaporated 
nearly to dryness on a steam bath. It was then transferred to a 



16 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

250 cubic-centimeter tared beaker and dried at 60° to 70° C. to 
apparent dryness, after which it was dried in vacuo at 80° C. until 
the loss between two successive weighings was negligible. For ash 
the residue was ground in a mortar, then placed in the vacuum oven 
over night and approximately one-half of the total sample used for 
the crude-ash determination. 

Acidity. — All acid determinations were made with fresh material. 
Two hundred grams of tomatoes were pulped and placed in a liter 
volumetric flask, made up to volume with cold distilled water, and 
toluol was added to prevent the growth of organisms. After stand- 
ing three days, 50 c. c. aliquots were titrated against approximately 
a tenth normal sodium-hydroxid solution (N/10 NaOH), using 
phenolphthalein as the indicator. No trouble was experienced in 
determining the end point. Separate determinations were made 
until the duplicates checked. In order to determine the effect of enzyms 
on acid content, a sample treated with boiling water was titrated 
three days later and the results compared with one using cold 
water. For the former, 200 grams of material required 14.28 c. c. 
N/10 NaOH, and for the same quantity of material employing cold 
water, 14.18 c. c. N/10 NaOH were required for neutralization. 

Free reducing substances. — One- tenth of the original alcoholic extract 
was evaporated nearly to dryness while the same part of the residue 
was being extracted on a filter paper with warm water (35° C). 
Very little reducing substance remained after extracting the original 
residue with alcohol, as described under "Sampling and preserva- 
tion," but the warm-water extraction was performed to insure the 
removal of final traces. The aqueous extract was combined with the 
residue from the alcoholic portion and filtered into a 250 c. c. volu- 
metric flask, after which the filter paper was thoroughly washed. 
One cubic centimeter of lead-acetate solution (a saturated solution 
of the normal salt) was added and the solution made up to volume 
at 20° C. The whole was filtered immediately and the excess of 
lead removed by adding approximately 0.5 gram of sodium oxalate. 
After standing a short time the mixture was filtered through dry 
filter paper and 10 c. c. of the clear solution used for the sugar deter- 
mination. The method used for determining reducing sugars was a 
combination of that of Bertrand (10), and that of Munson and 
Walker (33, 56). In this method the cuprous oxid is determined by 
titration, as in the Bertrand method, Fehling's solution and the 
time of heating are as specified by Munson and Walker. The Munson 
and Walker tables were used for the sugar equivalents. 

Total sugars. — Fifty cubic centimeters of the solution used for 
free reducing sugars were transferred to a 100 c. c. volumetric flask 
and 5 c. c. of HC1 (sp. gr., 1.19) added. The mixture was set aside 
over night and the flask made to volume at 20° C. the following morn- 



' PROCESS OF RIPENING IN THE TOMATO. 17 

mg. The solution was then neutralized and filtered and 20 e. c. 
used for reduction. 

Starch. — The residue from the water extraction of the sample used 
for reducing substances was placed in an Erlenmeyer flask and 
heated immersed in a boiling water bath for 2 1 hours with 150 c. c. 
of water and 15 c. c. of HC1 (sp. gr., 1.125). After cooling and 
neutralizing to phenolphthalein with NaOH, the mixture was made 
to 250 c. c. volume at 20° C. and filtered through a dry filter paper; 
20 and 50 c. c. aliquots of this solution were used for reduction. 

Pentosans.— A quantity of the original alcoholic extract represent- 
ing one- tenth of the total extract was evaporated nearly to dryness 
in an Erlenmeyer flask and one-tenth of the original residue added 
to this. Pentosans were determined by the furfural-phloroglucid 
precipitate method. The usual procedure is to distill over 360 c. c. 
and then to make up to 400 c. c. with a phloroglucin solution. It 
required 480 c. c. of distillate to obtain all of the furfural present, 
and 40 c. c. of phloroglucin solution were added to this. No correc- 
tion was made for the additional 120 c. c. distilled o^er. Krober's 
formulae were used in calculating the pentosan equivalents, as given 
in the Official and Provisional Methods of Analysis (57). 

Total nitrogen. — Two hundred cubic centimeters of the original 
alcoholic extract, representing one-tenth of the sample, were intro- 
duced into a Kjeldahl flask and evaported to dryness on the steam 
bath, and to this residue one-tenth of the original residue from 
the original sample was added. The total nitrogen in the aliquot 
was determined by the Kjeldahl method. 1 

Crude fiber. — A quantity of the residue representing three-twen- 
tieths of the sample was used for crude-fiber determination, which 
was made in the usual manner. 

ANALYTICAL DATA CONCERNING PROGRESSIVE CHANGES IN COMPO- 
SITION DURING RIPENING. 

The data showing progressive changes in composition during the 
process of ripening are assembled in Table IV. In section A of this 
table the percentages are referred to the weight of the entire fruit; 
in section B they are reduced to a basis of dry weight. Each entry 
in this table is a mean of two determinations, except as indicated by 
an asterisk (*), which shows that duplicate determinations were not 
made. 

Although the method of sampling has been described, it may not 
be amiss to emphasize the fact that each sample was a composite of 
fruits of the same maturity but of greatly varying sizes. The data 
with regard to average size and average weight at the various ages 
are found in Table III. 

1 All determinations of nitrogen reported in this investigation were carried out by the Nitrogen Laboratory, 
Bureau of Chemistry, United States Department of Agriculture. 

175085°— 20— Bull. 859 3 



18 



BULLETIN 850, U. S. DEPARTMENT OF AGRICULTURE. 



Table IV. — Progressive changes in the composition of Livingston Globe tomatoes during 

the process of ripening. 

[The asterisk (*) indicates that the given result is based upon a single determination; results not thus 
marked are the mean of two determinations.] 



Constituents. 



Age and color of fruit. 



14 days, 


21 days, 


green. 


green. 


*93. 250 


*94. 140 


*6. 750 


*5. 860 


5. 006 


3.824 


*. 634 


*. 562 


.320 


.585 


.19^ 

1.247 


.150 
.938 


1.743 


2.006 


.018 


.041 


1.724 


1.962 


1. 068 


.830 


.332 


.276 


*503 


*. 464 


5.450 


3.420 


3.647 


3.576 


1.743 


2.006 


1.903 


1.570 


99.100 


99. 801 


74. 120 


65. 250 


*9. 390 


*9. 590 


4. 740 


9. 980 


2.960 


2. 560 


18.500 


16.000 


25. 830 


34. 240 


.264 


.7ns 


25.560 


33.490 


15.840 


14. 220 


4.920 


4.700 


*7. 450 


*7. 920 


5.450 


3.420 


54. 030 


61.030 


25. 830 


34. 240 


28.200 


26. 790 



35 days, 


42 days, 


green. 


green. 


*94. 540 


*94. 240 


*S. 560 


*5. 760 


3.416 


3.385 


*. 509 


*. 497 


.883 


.640 


.1305 


.140 


.8156 


. 875 


2.143 


2.375 


.018 


.070 


2.125 


2.300 


.544 


. OOO 


.273 


. 264 


*. 4.84 


*. 433 


2.430 


3.710 


3.443 


3. 628 


2.143 


2.375 


1.300 


1. 2.53 


100. 192 


99. S70 


61. 440 


58. 760 


*9. 150 


*8. 620 


15. 880 


11.110 


2. 340 


2.440 


14. 660 


15. 250 


38. 550 


42. 230 


.323 


1.215 


38.200 


39.930 


9.770 


9.630 


4.890 


4.580 


*8. 710 


*7. 510 


2.430 


3.710 


61. 920 


63.970 


38. 550 


42. 230 


23.370 


21. 740 



56 days, 
turning. 



56 days, 
red. 



Sec. A. — Percentage of entire fruit: 

Moisture 

Total solids 

Sugar-free solids 

Ash, crude 

Acidity (as citric acid) 

Total nitrogen 

Protein (=N X 6.25) 

Total sugar (as invert) 

Cane sugar 

Reducing sugar (as invert > 

Starch 

Pentosans 

Crude fiber 

Ratio (sugar -=- acid) 

Carbohydrates- 
Total 

Soluble 

insoluble 

Determined constituents 

Sec B. — Percentage of dry matter: 

Sugar-free solids '...'. 

Ash, crude 

Acidity (as citric acid) 

Total nitrogen 

Protein(=N X 6.25.) 

Total sugar (as invert) 

Cane sugar 

Reducing sugar (as invert) 

Starch 

Pentosans 

Crude fiber 

Ratio (sugar h- acid) 

Carbohydrates — 

Total 

Soluble 

Insoluble 



*94. 140 
*5. 860 

3. 753 

*533 
.352 
.1365 
.853 

2.106 



2.112 
.616 
.247 

*. 447 



3.415 

2. 106 

1.309 

99.294 

64. 0-50 
*9. 090 

6.000 

2. 330 
14. 550 
35. 930 



36. 040 
10. 500 

4. 210 
*7. 630 

5.980 

58. 270 
35. 930 
22. 340 



*94. 450 

*5. 550 

2.994 

*. 484 

. 397 

.1225 

.766 

2.556 

.018 

2.537 

.222 

.228 

*423 

6.430 

3.429 

2.556 

.873 

99. 526 

53. 940 

*8. 720 

7.150 

2.200 

13. 7S0 

46.030 

.324 

45. 710 

4.000 

4.120 

*7. 620 

6.430 

01.720 
46. 030 
15. 690 



*94. 490 

*5.510 

2.847 

*.504 

. 420 

.116 

. 725 

2.667 

. 024 

2.637 

.146 

. 238 

*. 394 

6.340 

3.441 

2. 667 

.774 

99.580 

51. 670 

*9. 140 

7. 620 

2.100 

13. 130 

48.320 

. 435 

47.850 

2. 650 

4. 320 

*7. 150 

6.340 

62. 450 
48.320 

14. 130 



From Table IV it may be seen that the tomato contains a com- 
paratively small amount of solid matter and that a considerable 
portion of this consists of acids and sugars, especially in the ripe 
fruit. In fruit 14 days old there are relatively small percentages of 
acids and sugars, but as the tomato matures these increase per- 
ceptibly in the case of acids and markedly in the case of sugars. 
In general, throughout the ripening period there is an increase in 
moisture, acids, and sugars and a decrease in solids, total nitrogen, 
starch, pentosans, crude fiber, and ash. Some of these losses are 
probably not absolute, but attributable to changes in the proportion 
of the constituents. Tracing the figures for moisture content from 
the first column, concerning tomatoes 14 days old, across to the last 
column for ripe fruit, it will be seen that there is a gradual and 
progressive increase in total moisture. The only irregularity is that 
noticed in the fourth column (for 35 days). The moisture content 
here is greater than it should be if the change followed a regular 
curve of increasing water, being greater than in fruit when fully ripe. 



PROCESS OF RIPENING IN" THE TOMATO. 



19 



It seems that a clue to the reason for this irregularity is afforded by 
Table V, showing weather conditions for the period previous to pick- 
ing the samples. Just before picking this particular sample there 
was a rainfall of 9.10 inches within 36 hours. This precipitation 
was as unusual for the locality as it was injurious. Not only was 
the actual rainfall excessive, but the overflow from the Everglades 
still further complicated the situation. In some places a total loss 
resulted, and everywhere some damage was reported. At Peters, 
Fla., where the fruit for this investigation was grown, the loss was 
comparatively small, but the ground was saturated for more than a 
week. In view of the fact that the only anomalous moisture content 
was found in the 35-day fruit, it seems justifiable to correlate it with 
the excessive rainfall. It would hardly be warranted, however, to 
conclude from this one instance that the moisture content is higher 
after a heavy rain than normally. The coincidence is merely pointed 
out and should be of some interest in view of the widespread opinion 
in the canning industry that a heavy rainfall increases the amount 
of water in tomatoes. Bigelow (11) was recently unable to draw 
any definite conclusions with regard to this matter. 

Table V. — Weight and equatorial diameter of tomatois at dates when samples were taken, 
together with mean temperature and total precipitation for the period (usually seven days) 
preceding sampling. 



Time of sampling. 



Age 14 days. 
Age 21 days. 
Age 28 days. 
Age 35 days. 
Age 42 days. 
Age 56 days. 

Mean. 

Total. 



Color of fruit. 



Green 

do 

do 

do 

do 

Turning to red. 



Average 

weight 
(grams). 



6.74 
63.65 
82.37 
95.10 
147. 91 
162. 81 



Average 

diameter 

(cm.). 



2.31 
5.18 
5.47 
5.47 
6.37 
6.38 



Meteorological data. 



Tempera- 
ture (° F\). 



70 



Precipita- 
tion 
(inches). 



0.83 
.24 
.01 

9.42 
.27 
.09 



Inversely with moisture, total solids show a gradual decrease as 
the tomato matures. Turning to section B of Table IV, which gives 
the same data as those of section A of the same table, but reduced 
to a dry-weight basis, the sugar-free solids are seen to decrease con- 
siderably, while soluble carbohydrates increase and insoluble carbo- 
hydrates decrease regularly. Total carbohydrates vary somewhat, 
but in general seem to show an increase. 

Regarding the changes in acidity, there is considerable fluctuation, 
but when we consider the changes in a general way there is an increase 
in quantity from the second week to the fifth and then a gradual 
decrease during the last three weeks of ripening. The total quantity 
of acid found in the red-ripe fruit is, however, still greater than in 



20 



BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 



the first stage analyzed. The possibility should be borne in mind 
that the ripe tomato may contain relatively more acid salts and less 
free acid than the green fruit. Since the acid content was deter- 
mined throughout by titration to neutrality, with phenolphthalein 
as the indicator, it is obvious that the presence of acid salts might 
cause the analytical results to show more acid than the taste would 
indicate. As will be seen later, the change in the ratio of acid to 
sugar is in the direction to account for the sweetening that takes 

place during ripening. 
Nevertheless it is not 
impossible that the 
ratio of free-acid salts 
is likewise of impor- 
tance. 

It is believed that 
rainfall and other 
factors influence the 
quantity of acid in 
tomatoes, although 
there are few ana- 
lytical data at hand 
to indicate this. In 
the fourth column of 
figures of Table IV 
(sec. B), concerning 
the tomatoes that 
received the highest 
rainfall, the acidity 
is 15.88 per cent, and 
in the fifth column, 
where the tomato 
would no doubt be 
still affected, there 
is a decrease to 11.11 
per cent, but this fig- 
ure is higher than the 





















" 


























































! 6 








-^^^ 








^^•J 


... 






^^- -* 












^ r -- -—' 


S^ 




























^ 


1* — ^ 

it ^f^- 




i _ 




^"""""'■^li! 


• — -^x ■ 


yt ... Ifr1 , 


~ : r^- 


'K 

h 5 


=L- 

r 


r 

T =fe 


3 1 



Fig. 3. — Diagram showing the progressive changes in the composition 
of Livingston Globe tomatoes during ripening. The percentages are 
based upon dry weight. Curve a-a, acid; 6-6, pentosans; c-c, crude 
fiber; d-d, crude ash: e-e, starch;/-/, protein; g-g, soluble carbohy- 
drates (total sugar); h-h, insoluble carbohydrates; i-i, total carbo- 
hydrates; j-j, sugar-free solids. 



remaining ones. 
In this connection 
it may be worth while to suggest that a tomato with excessive water 
content may have the intercellular spaces sufficiently diminished so 
that gas exchange is impeded. Under such conditions a deficiency 
of oxygen might result in an accumulation of acid, due to incomplete 
oxidation of carbohydrates to carbon dioxid. 

The most striking change during ripening is that undergone by 
carbohydrates. In the first stage analyzed it was noticed particu- 
larly that insoluble carbohydrates composed o2.1 per cent of the 



PROCESS OF RIPENING IN THE TOMATO. 21 

total carbohydrates present, while in the last stage, that of ripe fruit, 
soluble carbohydrates were in excess, amounting to 77.3 per cent of 
the total. Nearly all of the total sugar in the tomato fruit is appar- 
ently invert sugar, and this increases from 25.56 per cent in the case 
of 14-day-old fruit to 48.32 per cent in ripe fruit, an increase of nearly 
89 per cent. Starch decreases during maturation from 15.84 to 2.65 
per cent. The most marked decrease, as would be expected, is no- 
ticed during the period of transition from green to red. The progres- 
sive decrease in starch during ripening is in striking contrast to the 
increase in starch noticed by Albahary (2). 

Pentosans decrease during ripening, but only to a comparatively 
slight extent. 

Total nitrogen decreases gradually during ripening and this fact 
is rather interesting and important in the light of some recent investi- 
gations of Kraus and Kraybill (28). They make the following 
statements: 

On account of the wide differences in composition of different parts of any plant 
grown under a given set of conditions, only similar portions are compared. With but 
few exceptions, increased amounts of total nitrogen are associated with decreased 
amounts of total carbohydrates. This condition holds fairly uniformly throughout 
the plant with the exception of the lower leaves. 

Examination of Table IV (sec. B) shows that increased total nitro- 
gen in the tomato fruit under the conditions used for the material in 
this investigation is associated with decreased total carbohydrates. 
The above investigators analyzed leaves and stems of the tomato 
plant, while the data presented in the present paper furnish ana- 
lytical figures for the fruit, thus yielding complete analyses of the 
entire plant. The correlation between total nitrogen and total 
carbohydrates holds with respect to the fruit as well as to the other 
parts of the plant (excluding the lower leaves). 

All of the changes during ripening are represented in the diagram 
shown as figure 3. 

COMPARISON OF THE COMPOSITION OF COMMERCIALLY PICKED 
TOMATOES WITH TURNING AND VINE-RIPENED FRUIT. 

It is conceded by many commission men and by some of the 
growers themselves that the tomatoes shipped to the North differ 
very noticeably in flavor and palatabilit} r from normal fruit. The 
chemical composition of Florida-grown tomatoes compares favorably 
with the various analyses reported of such fruit grown in other locali- 
ties, so the inferiority of the former can not be attributed to the kind 
of soil or climatic conditions prevailing in Florida. Elimination of 
these possibilities led the writer to look for other causes of the trouble. 
It will be seen from the analytical data which follow that tomatoes 
picked green and allowed to ripen exposed to air and light differ 



22 



BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 



slightly in composition from vine-ripened fruit. They contain more 
sugar-free solids, slightly more acid, and less total sugar than vine- 
ripened tomatoes, but these differences hardly explain the great 
difference in taste. In tracing the trouble to lack of ventilation it is 
believed that a proper explanation is presented. The analytical 
data upon which these conclusions are based are presented in Tables 
VI and VII. 



Table VI. — Composition of artificially ripened and vine-ripened Livingston Globe 

tomatoes. 

[The asterisk (*) indicates that the given result is based upon a single determination: results not thus 
marked are the mean of two determinations.] 





Commercially 
picked; green. 


Turning fruit. 
/ 


Vine- 


Constituents. 


As 
picked. 


Ripened 
at room 
tempera- 
ture. 


As 
picked. 


Ripened 
at room 
tempera- 
ture. 


ripened 

fruit; red 

ripe. 


Sec. A.— Percentage of entire fruit: 
Moisture 


*93.800 

*6.200 

3.975 

.508 

.138 

.831 

2.225 

.060 

2. 175 

*.855 

.258 

* 404 

4.380 

3.742 
2.225 
1.517 

64.110 
8.190 
2.140 

14.370 

35. 880 
.821 

34. 970 

*13. 790 

4.170 

*6. 520 
4.380 

60.870 
35. 880 
24.990 


*94.310 
*5.690 

3.059 
.475 
.1335 
.834 

2.631 
.012 

2.628 
.095 
.214 

*.462 

5.540 

3.403 

2.631 

.772 

53.770 
8.340 
2.340 

14.630 

40. 230 
.210 

46.010 
1.6S0 
3.770 

*8. 120 
5.540 

59.800 

46. 230 
13.670 


*94.450 
*5. 550 

2.994 
.397 
.1225 
.766 

2.556 
.018 

2.537 
.222 
.227 

*.423 

6.430 

3.429 

2.556 

.873 

53.940 
7.150 
2.200 

13.780 

46.030 
.324 

45.710 
4.000 
4.120 

*7.620 
6.430 

61.720 
46.030 
15.690 


*94.540 
*5. 460 

2.916 
.375 
.1265 
.791 

2.543 
.024 

2.518 
.101 
.251 

*.438 

6.780 

3.334 

2.543 

.791 

53.410 
6.860 
2.320 

14.500 

46.580 
.430 

46. 120 
1.850 
4.600 

*8.020 
6.780 

61.050 
46.580 
14.470 


*94.490 


Total solids 


*5. 510 


Sugar-free solids 


2.847 


Acidity (as citric acid) 


.420 


Total nitrogen 


.116 


Protein (=N X 6.25) 


.725 


Total sugar (as invert > 


2.667 


Cane sugar 


.024 


Reducing sugar (as invert) 


2.637 


Starch 


.146 


Pentosans 


.238 


Crude fiber 


*394 


Ratio (sugar -=- acid). . . 


6.340 


Carbohvdrates— 

Total 


3.441 


Soluble 


2.667 


Insoluble 


.774 


Sec. B.— Percentage of dry matter: 

Sugar-free solids 


51.670 


Acidity (as citric acid i '. 


7.620 


Total nitrogen 


2.100 


Total sugar (as invert) 


13. 130 
48.320 




.435 


Reducing sugar (as invert) 


47. 850 


Starch 


2.650 




4 320 


Crude fiber 


*7.150 


Ratio (sugar ~- acid) 


6.340 


Carbohvdrates— 

Total 


62. 450 


Soluble 


48. 320 


Insoluble 


14.130 







The percentage composition of samples of commercially picked 
green fruit (PI. I, A), of the same after being ripened at room tem- 
perature, of turning fruit as picked (PI. I, B) and after being ripened, 
and of vine-ripened fruit (PL II, C) is given in Table VI. All the 
fruit for the different samples was collected at the same time, in 
order that a comparison might be made. In the case of commer- 
cially picked green tomatoes, four crates were taken at random in one 
of the largest packing houses of the South. The fruit had just been 
picked and brought into the packing shed. The sample for analysis 



PROCESS OF RIPENING IN THE TOMATO. 23 

was taken from as representative a lot as could be obtained, portions 
of approximately 20 tomatoes being used. These had been ripened 
by exposure to air and light in the laboratory until they assumed a 
characteristic ripe appearance, as judged by the color. They were 
sampled 13 days later. Turning tomatoes were taken to the labora- 
tory after being picked and one lot sampled ; another lot was set aside 
to ripen. Four days later they showed a red color and were therefore 
sampled. Vine-ripened fruit was, of course, sampled as soon as it 
was brought into the laboratory. Table VI. summarizes the analyt- 
ical results obtained. Comparing the analyses of commercially 
picked green tomatoes with those given in Table IV, it will be seen 
that green fruits are not mature, for the chemical transformations 
of ripening have not been completed. The sugar-free solids are com- 
paratively high, while the sugars are correspondingly low. The total 
amount of carbohydrates is still low compared with that in mature 
fruit. Taking composition as a criterion of maturity, one must con- 
clude that commercially picked green fruits are immature and there- 
fore inferior. When green fruit is commercially ripened, however, 
changes take place, which, although corresponding in general trend 
to those of normal vine ripening, nevertheless fail to bring the fruit to 
the same degree of ripeness attained normally. The artificially 
ripened tomato is lower in total sugar than vine-ripened fruit (46.23 
per cent of the dry weight in the former, as contrasted with 48.32 per 
cent in the latter) and higher in acid (8.34 per cent, as contrasted 
with 7.62 per cent). The ratio of sugar to acid in the former is 5.54, 
while in the latter it is 6.34. In other words, the artificially ripened 
fruit is different in taste, due to the lack of one constituent and an 
excess of the other. In spite of these differences, however, the taste 
is not as bad as that of fruit which reaches the market. If some way 
could be devised to place on the market fruit having substantially the 
same flavor as that found in tomatoes ripened like the samples used, 
there would be little likelihood of complaint. 

When the data for turning tomatoes (Table VT) are examined, it 
is found that they compare more favorably with vine-ripened ma- 
ture fruit than the commercially picked green fruits. In the interval 
between the time when green tomatoes are picked in commercial 
practice and the time of turning red on the plant, sugar-free solids 
normally decrease considerably, while sugars increase in proportion. 
Since in turning tomatoes there is very little starch present which can 
be converted into sugar, it is seen that there is not so marked an in- 
crease of soluble carbonydrates in further ripening as in the artificial 
ripening of green-picked fruit. The acid content changed from 7.15 
to 6.86 per cent during ripening, but the latter figure is below that of 
normal fruit. The total amount of sugar is also below normal, but 
not as much so as in artificially ripened green tomatoes. The ratio 



24 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

in the case of ripened turnings is 6.7S, compared with 6.34 in vine- 
ripened fruit. This signified that the former should be comparatively 
sweet and less pronouncedly acid, as was indeed true. The facts 
brought out indicate that there is less chemical difference between 
turning and vine-ripened fruit than there is between commercially 
ripened green fruits and the latter. Differences in chemical compo- 
sition between vine-ripened fruit and commercially picked green to- 
matoes ripened in the laboratory, exposed to air and light, are not 
sufficient to account for the marked differences in flavor and palata- 
bility between commercially ripened fruit and normal fruit. This 
conclusion was confirmed by taste comparisons. 

EFFECT OF LACK OF VENTILATION ON RIPENING. 

Since the differences due to ripening after picking with normal 
exposure to the air were obviously insufficient to account for the in- 
feriority of Florida tomatoes after shipment, it seemed to be clearly 
indicated that the cause of the difficulty might well be lack of venti- 
lation during commercial ripening. As already stated, the fruits 
are wrapped before packing for shipment, and it seemed not unlikely 
that the paper used might appreciably retard gas exchange and thus 
modify the course of ripening. 

In order to test the hypothesis that wrapping plays an important 
part in influencing the composition and flavor of tomatoes, it was 
deemed necessary to analyze tomatoes which were ripened in a non- 
ventilated chamber and to compare the results with those obtained 
with wrapped fruit. Comparisons were made between (1) tomatoes 
commercially picked and ripened without ventilation, (2) commer- 
cially picked and ripened, wrapped with one paper, (3) commercially 
picked and wrapped with three papers, (4) commercially picked and 
ripened unwrapped at room temperature, (5) turnings ripened un- 
wrapped at room temperature, and (6) vine-ripened fruit. All of the 
fruit used for the above comparisons was obtained at the same time. 
A box for the green fruit ripened with no ventilation was made of 
composition board about a quarter of an inch thick. The approxi- 
mate size was a little less than 1 cubic yard. All corners were sealed 
with adhesive tape and the door was made by cutting it from the 
board and hinging it on. The total exclusion of air from the interior 
of the chamber of course was not secured, but the degree of nonven- 
tilation obtained was complete enough for the experiment, as shown 
by the fact that at times the oxygen content of the chamber would 
not support an alcohol flame. Six baskets of tomatoes (approxi- 
mately 125 fruits) were allowed to remain in this chamber, which was 
heated with one electric bulb, until they showed a red color. They 
were then removed and sampled by taking portions from 15 to 20 
fruits. It required 11 days for the color to appear. Other fruits 



PROCESS OF RIPENING IN THE TOMATO. 



25 



were wrapped with one and three papers and set aside at room tem- 
perature until they also attained a red color. These were sampled 11 
days later. Summaries of the analyses are given in Table VII. 

Table VII. — Composition of commercially picked green Livingston Globe tomatoes 
allowed to ripen under different conditions as compared with artificially ripened turnings 
and vine-ripened red fruits. 

[The asterisk (*) indicates that the given result is based upon a single determination; results not thus 
marked are the mean of two determinations.] 



Constituents. 



Sec. A. — Percentage of entire fruit: 

Moisture 

Total solids . .■ 

Sugar-free solids 

Acidity (as citric acid) 

Total nitrogen 

Protein (=N X 6.25) 

Total sugar (as invert) 

Cane sugar 

Reducing sugar (as invert) 

Starch «;. 

Pentosans : .': 

Crude fiber 

Ratio (sugar -s- acid) 

Carbohydrates — 

Total 

Soluble 

Insoluble 

Sec. B. — Percentage of dry matter: 

Sugar-free solids 

Acidity (as citric acid) 

Total nitrogen 

Protein (=N X 6.25) 

Total sugar (as invert) 

Cane sugar 

Reducing sugar (as invert) 

Starch 

Pentosans 

Crude fiber 

Ratio (sugar ■*• acid) 

Car boh y drates — 

Total 

Soluble 

Insoluble 



Commercially picked; ripening — 


Turning 










fruit; 
ripened 










No ven- 


One pa- 
per wrap- 


Three pa- 
per wrap- 


At room 
tempera- 


at room 
tempera- 




ping. 


pings. 


ture. 


ture. 


*93. 930 


*94. 500 


*94. 430 


*94.310 


*94. 540 


*6. 070 


*5.500 


*5. 570 


*5. 690 


*5. 460 


3.745 


3.037 


3.039 


3. 059 


2.916 


1.104 


.850 


.673 


.475 


.375 


*134 


.131 


.1265 


.1335 


. 1265 


* 838 


.818 


.791 


.834 


.791 


2.325 


2.462 


2.531 


2.631 


2.543 


.048 


.012 


.077 


.012 


.024 


2. 275 


2.450 


2. 450 


2.628 


2.518 


.079 


.084 


.139 


.095 


.101 


.255 


.224 


.238 


.214 


.251 


*. 482 


*.4S2 


*.473 


*.462 


*.43S 


2.110 


3.010 


3.760 


5.540 


6.780 


3.140 


3.253 


3.381 


3.403 


3.334 


2.325 


2.463 


2.531 


2.631 


2.543 


.815 


.790 


.850 


.772 


.791 


61.700 


55.050 


54. 550 


53.770 


53.410 


18. 180 


15. 450 


12.080 


8.340 


6.860 


*2.210 


2.380 


2.270 


2.340 


2.320 


*13.810 


14. 670 


14.190 


14.630 


14. 500 


38.290 


45. 950 


45. 440 


46.230 


46. 580 


.791 


.218 


1.382 


.210 


.430 


37. 450 


44. 540 


43.980 


46. 010 


46. 120 


1.301 


1.620 


2.500 


1.680 


1.850 


4.190 


4.080 


4.270 


3.770 


4.600 


*7. 940 


*8. 760 


*8. 490 


*8. 120 


*8. 020 


2.110 


3.010 


3.760 


5.540 


6.780 


51. 730 


60. 400 


60.700 


59.800 


61.050 


38.290 


45. 950 


45. 440 


46.230 


46. 580 


13. 440 


14.450 


15.260 


13. 670 


14. 470 



Yinp- 
ripened 

fruit; 
red ripe. 



*94.490 
*5. 510 

2.847 
.420 
.116 
.725 

2.667 
.024 

2.637 
.146 
.238 

*.394 

6.340 

3.441 

2. 667 

.774 

51.670 
7.620 
2.100 

13. 130 

48. 130 
.435 

47.850 
2.650 
4.320 

*7. 150 
6.340 

62. 4.50 
48.320 
14. 130 



There are striking differences in the analyses between the acid 
and carbohydrate content of tomatoes commercially picked and 
ripened without ventilation and the same fruit ripened when exposed 
to the air. Without ventilation the acids are very high and the 
soluble carbohydrates (sugars) are low. These facts indicate incom- 
plete oxidation of carbohydrates to carbon dixoid (C0 2 ) with the 
consequent accumulation of acid. The connection of these changes 
in composition with the flavor is very obvious. The nonventilated 
fruit was markedly inferior. Although the reaction was decidedly 
acid, the general flavor was insipid. While the same effect was not 
produced to as great an extent in fruit ripened when wrapped with 
paper, it nevertheless takes place. Fruit wrapped with one paper 
had a noticeably inferior flavor; it was not as poor as the sample 
ripened without ventilation, but it was worse than that of green 



26 



BULLETIN 850, IT. S. DEPARTMENT OF AGRICULTURE. 



fruit ripened without wrapping. The acid content of fruit ripened 
without ventilation shows an increase of approximately 138 per cent 
over that of vine-ripened fruit; that of fruit ripened while wrapped 
with one paper, an increase of approximately 102 per cent; and that 
of fruit ripened while wrapped with three papers, an increase of about 
58 per cent. The soluble carbohydrate content for fruit ripened 
without ventilation shows a decrease of nearly 21 per cent compared 
with normal fruit; that of fruit ripened while wrapped with one 
paper, a decrease of nearly 5 per cent; and that of fruit ripened 
while wrapped with three papers, a decrease of nearly 6 per cent. 

The data presented also bring out the fact that green tomatoes 
ripened when exposed to air and unwrapped are superior in taste 
and chemical composition to the same fruit ripened when wrapped 
with paper. 

Several experiments were carried out in order to determine what 
effect lack of ventilation produced on the normal color of the tomato. 
Since they all yielded the same results, it will suffice to present the 
figures from one. Two large glass jars were filled with green fruit 
and cardboard covers placed over each. Unwrapped fruits were 
placed in baskets as checks. Both lots were held at room tempera- 
ture and examined at the same time. (Table VIII.) . 

Table VIII. — Effect of lack of ventilation on the normal coloring of tomatoes held at 

room temperature. 





21 fruits in bottles 
(no ventilation). 


31 fruits in baskets (ventilated). 


Time of examination. 


Green. 


Turning. 


Green. 


Colored. 




Turning. 


Pink. 


Red. 


Total. 




21 




6 


10 


6 
5 


9 
a 26 


25 




21 


31 













o 14 soft. 

These results would seem to indicate that lack of ventilation 
retards ripening and the consequent formation of pigment in the 
tomato. It was noticed that the tomatoes kept in jars were firmer 
than those left exposed to the air. Hill (24) records a similar 
condition in the case of peaches held in an atmosphere of carbon 
dioxid (C0 2 ). His explanation is that C0 2 evidently prevents the 
hydrolysis of the pectin to which peaches owe their hardness. This 
may also be the case with tomatoes. An attempt was made to 
duplicate the results presented above by using a larger closed chamber 
and also by wrapping the fruit in paper, but no concordant data 
were obtained. There are hardly sufficient data to justify making 
any statement as to the effect of wrapping on the color formation. 
It is often noticed that tomatoes picked green and ripened arti- 



PROCESS OF RIPENING IN THE TOMATO. 27 

ficially acquire a much better color than vine-ripened fruit. The 
color is deeper and more even. 

Investigation has been made by Duggar (17) of the effect of various 
conditions on the development of the tomato pigment (called by 
this author lycopersicin) . He studied the effect of light and tempera- 
ture on its development and concluded that high color is independent 
of any direct effect of light and that fruit will redden perfectly in 
darkness at a temperature of even 20° to 25 Q C. He also states that 
"when half-grown varieties are employed a temperature of 30 Q C. 
is sufficient to suppress lycopersicin development to a marked extent. 
Fruits nearer maturity, that is, those showing a blush of color, permit 
a stronger lycopersicin development at all temperatures employed." 
Duggar (17) also studied the relation of oxygen to pigment produc- 
tion in the tomato and concluded that lack of oxygen inhibited 
lycopersicin development. 

From a consideration of all the data it appears that wrapping is 
harmful to the tomato and that lack of ventilation is probably the 
main cause of inferiority in taste and keeping quality. 

In 1913 Hill (24) reported on the respiration of fruits and growing 
plant tissues in certain gases with reference to ventilation and fruit 
storage. He found that apples and peaches ripened poorly when 
oxygen was withheld from them. It was also pointed out that an 
accumulation of carbon dioxid within paper wrappers in which 
peaches are shipped and an insufficient supply of oxygen cause 
"ice scald." 

Fischer and Nelson (18) recently came to a similar conclusion 
with regard to wrapping cantaloupes, maintaining that "wrapped 
cantaloupes do not refrigerate so well in transit nor do they reach 
the consumer in as good condition as do cantaloupes not wrapped." 
In both of these investigations similar conditions were found to be 
the result of wrapping, namely, that wrapped fruits were firmer 
but of poorer quality than those unwrapped. 

Another serious disadvantage of the present method of picking and 
shipping green tomatoes lies in the fact that it is practically impossible 
to determine comparable stages of maturity in picking. In spite of 
the fact that the fruit of individual baskets is all approximately of the 
same size, the coloring of the fruit does not occur at the same time. 
The explanation for this fact has already been given. The maturity 
of a tomato depends on its age and not on its size; consequently 
fruits of the same size do not necessarily ripen and turn red simulta- 
neously. The most obvious disadvantage of the inability to deter- 
mine comparable stages of maturity is the fact that when the fruit 
does ripen, either in transit or after reaching the market, it colors up 
so irregularly that many sortings become necessary before the dealer 
is able to dispose of it. The more uniform in size and color a package 
is the more salable it is, so naturally the dealer sorts the fruit to insure 



28 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

a quick sale. In consequence of many handlings the fruit becomes 
soft and injured and is more liable to fungous attacks through the 
germination of adhering spores. It is clear that, if possible, only fruit of 
the same age should be packed in a single container. No criterion for 
determining age exists except at the time of turning from green to pink. 
If turning tomatoes could be packed instead of green ones, this particular 
commercial difficulty would be solved. Since it has been shown, 
moreover, that Florida tomatoes are lacking in certain fundamental 
qualities as to taste, which would likewise be remedied by picking 
more mature fruit, the writer turned his attention to determining the 
feasibility of shipping "turnings." It was found, as would of course 
be expected, that the riper the tomatoes the shorter the time it is pos- 
sible to hold them, but the fact was ascertained that " turnings" can 
be kept in good condition at a temperature approximating that ob- 
tained in refrigerator cars (50° to 55° F.) long enough to ship them and 
to sell them to the consumer. Turning tomatoes held in the refrigerator 
for 10 days and then kept at a temperature of approximately 75° F. 
for 5 days longer were found to be in an excellent condition. Other 
fruits remaining at the lower temperature for 15 days were still firm 
enough to be held at room temperature for a few days. At lower 
temperatures than those used it is possible to hold tomatoes even 
longer than 15 days. Iced shipments in pony refrigerators sent by 
express from Miami, Fla., to Washington, D. C, arrived in excellent 
condition. One commission man who has been shipping fruit under 
ice for a number of years states that these tomatoes reach the market 
in excellent condition and bring higher prices than uniced fruit. The 
above statements are not offered as recommendations for picking and 
shipping turning tomatoes under ice. There are, however, many good 
reasons for suggesting that turning fruit may be picked and shipped 
under an initial icing. One of these reasons has already been men- 
tioned, namely, that it would be possible to pick fruit at the same stage 
of maturity which would ripen uniformly and save considerable of the 
loss which is at present experienced. Furthermore, chemical analysis 
has shown that turning fruit compares favorably with normal or vine- 
ripened fruit in composition, taste, and palatability. Other investi- 
gators, Powell (38), Ramsey (39, 40, 41), Stevens and Wilcox (47, 
48), Ridley (42), and others, have shown that fruits are more liable to 
fungous infection when they are wounded than when uninjured. This 
is what one would expect in the light of some recent investigations 
which show a high correlation between susceptibility to infection and 
the resistance offered by the fruit to mechanical puncture. 

The investigations of Rosenbaum (43) on the origin and spread of 
tomato fruit rots in transit have demonstrated that overripeness, 
bruises, and other injuries favor the appearance of these rots. Since 
the resistance of the epidermis shows the relative ease with which a 
fruit may become infected by means of a mechanical entrance of the 



PROCESS OF RIPENING IN THE TOMATO. 



29 



spore tube, tables are presented showing these data in connection with 
tomatoes. Table IX (sec. A) shows the pressure necessary to penetrate 
the epidermis of fruit of different ages. The epidermis of colored fruit 
is softer than that of green tomatoes 38 days old, ret the difference is 
too small to justify the conclusion that green fruits are preferable on 
this account. Table IX (sec. B) also shows the effect of temperature 
on the resistance of the epidermis to wounding. These results indi- 
cate that tomatoes are less liable to injury when cooled than when 
they are warm and consequently are less liable to fungous infection. 
It is generally known .also that respiration decreases considerably 
with the lowering of temperature. The products causing the inferior 
taste and flavor in tomatoes probably result from intramolecular 
respiration as a result of withholding free oxygen from the tissues. 
Under the present methods of shipping tomatoes from the South it 
would be impossible to allow cars to remain open throughout the 
entire journey. The. initial icing of cars at the warm end of the trip 
would have the effect of preventing the harmful result of lack of 
ventilation by reducing respiration to a minimum. 

Table IX. — Effect of age and temperature upon the resistance to wounding of the epi- 
dermis of Livingston Globe tomatoes, showing also color conditions. 1 





Sec.A. 


— Ageoftomatoes. With needle hav- 
ing a diameter of 68 microns. 


Sec. B. — Temperature ef- 
fects. With needle hav- 
ing a diameter of — 


Descriptive data. 


7 
days; 
green. 


13 
day?: 
green. 


21 
days; 
green. 


30 

days: 
green. 


38 

days: 
green. 


49 
days; 
turn- 
ing. 


68 microns: 
turning. 


7S microns; 
red ripe. 


Temperature of penetration 
(°C.) 


30 

41.3 

40.9 

40.6 
41.2 
41.0 
39.6 
41.3 
41.7 
41.9 


29 

3S.3 
36.3 

37.1 
37.3 
40.3 
40.3 
36.6 
37.6 
36.6 
37.5 
39.8 
39.3 
37.4 
37.1 
38.8 
36.8 
38.4 
39.3 
39.5 
36.4 


29 

23.6 
27.8 
32.0 
33.9 
32.1 
31.5 
29.3 
34.7 
31.5 
34.2 
32.1 
30.5 
26.3 
31.3 
22.6 
29.8 
29.5 
32.3 
24.9 
28.9 


30 

14.4 
23.2 
21.3 
20.4 
23.7 
24.8 
24.9 
25.6 
25.1 
25.5 
27.7 
25.0 
21.6 
28.1 
25.4 
25.6 


33 

32.4 
33.3 
28.2 
24. g 
30.5 
32.6 
25.8 
18.6 
32.2 
30.5 
27.5 
28.8 
30.0 
31.5 
33.9 
30.4 
27.8 


30. :» 

33.8 
31.6 
29.5 
30.7 
32.0 
32.6 
32.3 
26.1 
37.0 
30.2 
32. 6 
30.5 
29.1 
30.1 
28.7 


24 

23.91 
32.81 
21.40 
22.97 
25.35 
27.38 
25.38 
IS. 47 
24.35 
27.80 
29.19 


9 

15.75 
28: 54 
16. 70 

IS. 60 
20.60 
23.54 
23.30 
li>. 27 
20.38 
25.08 
25.72 


25 

32.48 
30.87 


14 


Average of 10 sea!e readings at 
which penetration occurred 
for individual tomatoes: _ 
No. 1 


30.92 


No. 2 


31.21 


No. 4 


32.16 2S.64 
26.36 24 ..05 


No. 5 


28.91 1 22.03 


No. 6 


27.95 27.84 


No. 7 


31.32 1 29.32 


No. 8 


31.86 29.42 


No. 9 


23.60 23.79 


No.10 


26.61 28.46 


No 11 




No 12 







No 13 












No 14 












No 15 












No 16 












No 17 














No 18 














No 19 
















No 20 




































Average scale reading for entire 


40.8 

11.75 

14.63 

2.88 


38.0 

10.86 
14.03 

3.77 


30.5 
8.49 
14.63 

6.14 


23.8 
0.3S 
14.63 

8.25 


29.3 
8.11 
18.91 

10.80 


31.1 
8.67 
18.91 

10.24 


25.35 
13.20 
23.48 

10.28 


21.33 
11.80 
23.48 

11.68 


29.32 
6.96 

12.04 

5.08 


27.0 


Due to tension of spring. grams 
Weight of needle and rod. . . do. . 
Pressure necessary to punc- 


6.46 

12.04 

5.58 



1 For detailed information as to the apparatus and methods used to obtain the data presented in this 
table, see the following references: Hawkins and Harvev (22): Hawkins and Sando (23): Rosenbaum and 
Sando (44). 



30 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

Against the arguments in favor of picking and shipping turning 
fruit one must consider the advantages of present practices. The 
picking of turning fruit would require that the fields be gone over 
more frequently than at present and that the pickers exercise much 
more judgment and care. The writer had planned to make com- 
mercial shipments of tomatoes picked at the turning stage in order 
to get dependable information which might serve as a basis for rec- 
ommending to the growers changes in the current practice, but the 
discontinuance of this work for the present has prevented the carrying 
out of the plan. It is of very great importance to the growers that 
these shipments be made. It is felt that the work reported upon in 
this bulletin supports the chemical explanation offered of the infe- 
riority of tomatoes shipped from the east coast of Florida during the 
winter and spring months. It remains to be determined whether 
the changes in current practice suggested in these pages can be put 
into effect. If they can be, the result of these investigations will 
be to insure the consumer a better product in the future than in the 

past. 

SUMMARY AND CONCLUSIONS. 

With the particular object of discovering the chemical basis for 
the inferiority of commercially picked and ripened Florida tomatoes 
marketed in the North during the winter and spring, a series of anal- 
yses has been made of tomatoes of several degrees of maturity and 
of tomatoes ripened artificially under various conditions of venti- 
lation. 

It was found that the only way to secure samples of comparable 
maturity for analysis was to tag the blossoms and pick the fruit at a 
definite age. There is a wide range of variation in the size of the 
tomatoes within the same variety, but ripening proceeds at a uni- 
form rate regardless of size. Maturity is dependent upon age, not 
upon size. 

Using fruit of known age, therefore, analyses were made which 
indicate that in general throughout the ripening period there is an 
increase in moisture, acids, and sugars and a decrease in solids, total 
nitrogen, starch, pentosans, crude fiber, and ash. 

The most striking change which occurs during ripening is that 
undergone by carbohydrates. Sugars increase from 25.66 per cent 
in fruit 14 days old to 4S.32 per cent in ripe fruit. 

Starch decreases in the same interval from 15.84 to 2.65 per cent. 
The most marked decrease takes place during the period of transition 
from green to red. 

The percentage composition of fruit picked green but ripened with 
free access of air compared with analyses of turning and vine-ripened 
fruit did not show enough variation to account for the great differ- 



PROCESS OF RIPENING IN THE TOMATO. 31 

• 

ences in taste found in commercially shipped fruit. Turning toma- 
toes showed less difference from vine-ripened fruit than did the green 
fruit and compared favorably with normal tomatoes not only in 
composition but also in taste. 

The effect of lack of ventilation on ripening was to increase the 
acid content approximately 138 per cent over that of vine-ripened 
fruit. The flavor of tomatoes ripened without ventilation was very 
inferior. The soluble carbohydrate content showed a decrease of 
nearly 21 per cent. Commercially ripened green fruit, wrapped with 
one paper, showed an increase in acid of approximately 102 per cent 
and a sugar decrease of nearly 5 per cent compared with correspond- 
ing tests of vine-ripened tomatoes. The results of wrapping with 
three papers were less marked and are difficult to explain. 

The data seem to justify the conclusion that wrapping probably 
modifies the course of ripening to such an extent as to account for 
marked changes in taste and flavor. The combined results of pick- 
ing fruit green, of wrapping, and of closing the cars in transit probably 
account for the total differences existing in quality between com- 
mercially shipped and vine-ripened tomatoes. 



LITERATURE CITED. 

Albahary, J. M. 

(1) 1907. Analyse complete du fruit du Lycopersicum esculentum ou tomate. 

In Compt. Rend. Acad. Sci. [Paris], t. 145, no. 2, p. 131-133. 

(2) 1908. Etude chimique de la maturation du Lycopersicum esculentum 

(tomate). In Compt. Rend. Acad. Sci. [Paris], t. 147, no. 2, p. 
146-147. 

(3) Alwood, W. B. 

1891. Tomatoes. Va. Agr. Exp. Sta. Bui. 9, 18 p. 

(4) ■ — ■ — — and Bowman, Walker. 

1890. A study of tomatoes. Va. Agr. Exp. Sta. Bui. 4, 18 p. 

(5) Babcock, S. M. 

1883. [Analysis of the] tomato. In N. Y. State Agr. Exp. Sta. 1st Ann. Rpt. 
1882, p. 24. 

(6) Bacon, R. F., and Dunbar, P. B. 

1911. Changes taking place during the spoilage of tomatoes, with methods 

for detecting spoilage in tomato products. U. S. Dept. Agr., Bur. 
Chem. Cir. 78, 15 p. 

(7) Bailey, L. H. 

1892. Do fertilizers affect the quality of tomatoes? In N. Y. Cornell Agr. 

Exp. Sta. Bui. 49, p. 456-458. 

(8) — and Lodeman, E. G. 

1891. Notes on tomatoes. N. Y. Cornell Agr. Exp. Sta. Bui. 32, p. 143-189. 

(9) Berard, M. 

1821. Suite du memoire sur la maturation des fruits. Ann. Chim. et Phys., 
t. 16, p. 225-251. 

(10) Bertrand, Gabriel. 

1906. Le dosage des sucres r£ducteurs. Bui. Soc. Chim. Paris, s. 3, t. 35, 
p. 1285-1299. 

(11) Bigelow, W. D. 

1917. Report on canned vegetables. In Jour. Assoc. Off. Agr. Chem., v. 
3, no. 1, p. 1-21. 

(12) Bishop, W. H., and Patterson, H. J. 

1890. Experiments with tomatoes. Md. Agr. Exp. Sta. Bui. 11, p. 47-74. 

(13) Briosi, Giovanni, and Gigli, Torquato. 

1890. Su la composizione chimica e la struttura anatomica del frutto del 
pomodro (Lycopersicum esculentum Mill.). In Staz. Sper. Agr. 
Ital., v. 18, fasc. 1, p. 5-34. 

(14) Caldwell, G. C. 

1892. The determination of sugar in the tomato. N. Y. Cornell Agr. Exp. 

Sta. Bui. 49, p. 399-400. 

(15) Congdon, L. A. 

1912. A further study of the tomato with special reference to canned tomatoes. 

In N. Dak. Agr. Exp. Sta. 23d Ann. Rpt., 1912, pt. II, p. 216-242. 

(16) Dahlen, H. W. 

1875. Beitrage zur chemischen Kenntniss der Gemusepflanzen. In Landw. 
Jahrb.,Bd. 4, p. 613-721. 
32 



PROCESS OF RIPENING IN THE TOMATO. 33 

(17) Duggar, B. M. 

1913. Lycopersicin, the red pigment of the tomato, and the effect of condi- 
tions upon its development. In Wash. Univ. Studies, v. 1, pt. 1, 
no. 1, p. 22-45. Literature, p. 44-45. 

(18) Fischer, G. L., and Nelson, A. E. 

1918. More care is needed in handling western cantaloupes. U. S. Dept. 

Agr., Bur. Markets Doc. 9, 11 p., 4 fig. 

(19) Formenti, Carlo, and Scipiotti, Aristide. 

1906. Zusammensetzung italienscher Tomatensafte. In Ztschr. Untersuch. 
Nahr. u. Genussmtl., Bd. 12, Heft 5, p. 283-295. 

(20) Gore, H. G, and Fairchild, David. 

1911. Experiments on the processing of persimmons to render them nonas- 
tringent. U. S. Dept. Agr., Bur. Chem. Bui. 141, 31 p., 5 fig., 3 pi. 

(21) Hasselbrino, Heinrich, and Hawkins, L. A. 

1915. Pysiological changes in sweet potatoes during storage. In Jour. Agr. 
Research, v. 3, no. 4, p. 331-342. Literature cited, p. 341-342. 

(22) Hawkins, L. A., and Harvey, R. B. 

1919. Physiological study of the parasitism of Pythium debaryanum Hesse 

on the potato tuber. In Jour. Agr. Research, v. 18, no. 5, p. 275-297, 
2 fig., pi. 35-37. Literature cited, p. 295-297. 

(23) — and Sando, C. E. 

1920. Effect of temperature on the resistance to wounding of certain small 

fruits and cherries. IT. S. Dept. Agr. Bui. 830, 6 p., 1 fig. 

(24) Hill, G. R., jr. 

1913. Respiration of fruits and growing plant tissues in certain gases, with 
reference to ventilation and fruit storage. N. Y. Cornell Agr. Exp. 
Sta. Bui. 330, p. 377-408. Bibliography, p. 407-408. 

(25) Huston, H. A., and Bryan, A. H. 

1901. The chemical composition of materials. In Ind. Agr. Exp. Sta. 13th 
Ann. Rpt., [1899J/1900, p. 80-88. 

(26) Jenkins, E. H., and Britton, W. E. 

1896. On the use of commercial fertilizers for forcing-house crops. Experi- 
ments with tomatoes. In Conn. Agr. Exp. Sta. 19th Ann. Rpt., 
1895, p. 75-90. 

(27) Kennedy, C. W. 

1873. Solania in Solanum lycopersicum. Amer. Jour. Pharm., v. 45 (s. 4, 
v. 3), p. 8-9. 

(28) Kraus, E. J., and Kraybill, H. R. 

1918. Vegetation and reproduction with special reference to the tomato. 
Oreg. Agr. Exp. Sta. Bui. 149, 90 p., 22 fig. Literature cited, p. 
87-90. 

(29) Lloyd, F. E. 

1911. Carbon dioxide at high pressure and the artificial ripening of persim- 
mons. In Science, n. s., v. 34, no. 887, p. 924-928. Citations, p. 928. 

(30) McElhenie, T. D. 

1872. Lycopersicum esculentum. — Tomato. In Amer. Jour. Pharm., v. 44, 
p. 197-200. 

(31) MlLLARDET, A. 

1876. Note sur une substance colorante nouvelle (Solanorubine) decouverte 
dans la tomate. Nancy, 1876. (Abstract.) In Just's Bot. Jahres- 
ber., Jahrg. 4, p. 783-784. 1876. Original not seen. 



S4 BULLETIN 850, U. S. DEPARTMENT OF AGRICULTURE. 

(32) Montanari, Carlo. 

1904. Materia colorante rossa del pomodoro. In Staz. Sper. Agr. Ital., v. 37, 
fasc. 10, p. 909-919. 

(33) Munson, L. S., and Walker, P. H. 

1906. The unification of reducing sugar methods. In Jour. Amer. Chem. 
Soc, v. 28, no. 6, p. 663-686. 

(34) Palmeri, P. 

1885. Sul pomodoro. In Ann. R. Scuola Sup. Agr. Portici, v. 5, p. 67-83. 

(35) Passerini, N. 

1890. Sulla composizione chimica del frutto del pomodoro. (Solanum 
lycopersicum L.) In Staz. Sper. Agr. Ital., v. 18, fasc. 5, p. 545-572. 

(36) Patterson, J. 

1889. Report of the chemist. In Md. Agr. Exp. Sta. 2d Ann. Rpt., 1889, 
p. 67-93. 

(37) Peckolt, Th. 

1909. Heil- und Nutzpnanzen Brasiliens. In Ber. Deut. Pharm. Gesell., 
Jahrg. 19, Heft 3, p. 180-207. 

Cites early analyses of John and Bertagnini. 

(38) Powell, G. H., et al. 

1908. The decay of oranges while in transit from California. U. S. Dept. 
Agr., Bur. Plant Indus. Bui. 123, 79 p., 26 fig., 9 pi. (2 col.). 

Ramsey, H. J. 

(39) 1915. Factors governing the successful shipment of red raspberries from the 

Puyallup Valley. XJ. S. Dept. Agr. Bui. 274, 37 p., 26 fig. 

(40) 1915. Handling and shipping citrus fruits in the Gulf States. U. S. Dept. 

Agr., Farmers' Bui. 696, 28 p., 10 fig. 

(41) 1916. The handling and shipping of fresh cherries and prunes from the 

Willamette Valley. U. S. Dept. Agr. Bui. 331, 28 p., 11 fig. 

(42) Ridley, V. W. 

1918. Factors in transportation of strawberries from the Ozark region. U. S. 
Dept. Agr., Bur. Markets Doc. 8, 10 p., 6 fig. 

(43) Rosenbaum, Joseph. 

1918. The origin and spread of tomato fruit rots in transit. In Phytopath- 
ology, v. 8, no. 11, p. 572-580, 1 fig., pi. 4. 

(44) and Sando, C. E. 

1920. Correlation between the size of the fruit and the resistance of the 
tomato skin to puncture and its relation to infection with Macro- 
sporium tomato Cooke. In Amer. Jour. Bot., v. 7, no. 2, p. 78-82. 

(45) Schunck, C. A. 

1903. The xanthophyll group of yellow colouring matters. In Proc. Roy. 
Soc. London, v. 72, no. 479, p. 165-176, pi. 6-7. 

(46) Snyder, Harry. 

1899. Tomatoes. Composition and food value. In Minn. Agr. Exp. Sta. 
Bui. 63, p. 513-517. 
Stevens, N. E., and Wilcox, R. B. 

(47) 1917. Rhizopus rot of strawberries in transit. U. S. Dept. Agr. Bui. 531, 

22 p., 1 fig. Literature cited, p. 21-22. 

(48) 1918. Further studies on the rot of strawberry fruits. U. S. Dept. Agr. Bui. 

686, 14 p. 



PROCESS OF RIPENING IN THE TOMATO. 35 

(49) Street, J. P. 

1911. Report on vegetables. In U. S. Dept. Agr., Bur. Chem. Bui. 137, 
p. 122-134. 

(50) Stuber, W. 

1906. tiber die Zusammensetzung der Tomate und des Tomatensaftes. In 

Ztschr. Untersuch. Nahr. u. Genussmtl., Bd. 11, Heft 10, p. 578-581. 

(51) Thompson, Firman, and Whittier, A. C. 

1913. Forms of sugar found in common fruits. Proc. Soc. Hort. Sci., 9th 
Ann. Meeting, 1912, p. 16-22. 

(52) Tracy, W. W. 

1907. Tomato culture . . . , 150 p., illus. New York. 

(53) U. S. Department op Agriculture. Office of Experiment Stations. 

1893. Composition of vegetables. In U. S. Dept. Agr. Off. Exp. Stas. Bui. 
15, p. 401. 

(54) Van Slyke, L. L., Taylor, O. M., and Andrews, W. H. 

1905. Tabulated analyses showing amounts of plant-food constituents in 
fruits, vegetables, etc. In N. Y. Agr. Exp. Sta. Bui. 265, p. 223-230. 

(55) Voorhees, E. B. 

1889. Experiments on tomatoes. N. J. Agr. Exp. Sta. Bui. 63, 27 p. 

(56) Walker, P. H. 

1907. The unification of reducing sugar methods. In Jour. Amer. Chem. 

Soc, v. 29, no. 4, p. 541-554. 

(57) Wiley, II . W., ed. 

1908. Official and provisional methods of analysis, Association of Official 

Agricultural Chemists. As compiled by the committee on revision 
of methods. U. S. Dept. Agr., Bur. Chem. Bui. 107 (rev.), 272 p., 
13 fig. Reprinted in 1912. 

(58) WlLLSTATTER, RlCHARD, and EsCHER, II. H. 

1910. Uber den Farbstoffe der Tomate. In Ztschr. Physiol. Chem., Bd. 64, 
Heft 1, p. 47-61, pi. 2 (col.). 



Bui. 859, U. S. Dept. of Agriculture. 



Plate III, 





Exterior of a Normal and of a "Puffy" Tomato. 



Bui. 859, U. S. Dept. of Agriculture. 



Plate IV. 





Interior of a Normal and of a "Puffy" Tomato. 



APPENDIX. 

COMPARISON OF THE COMPOSITION OF "PUFFY" AND NORMAL 
LIVINGSTON GLOBE TOMATOES. 

The abnormality in tomatoes called puffiness is one in which the 
seed cavities are affected. The fruit sounds hollow when it is patted 
with the hand and shows external angular irregularities. Plates III 
and IV show the angular appearance of the exterior and also the 
characteristic appearance of the interior of the fruit. In a locality 
where the trouble was especially pronounced one crate of tomatoes 
was taken at random from a packing house and the number of 
hollow and normal fruits estimated. The figures follow: Estimated 
by the sound before cutting, normal 58, hollow 95; estimated by 
cutting the fruit in two, normal 32, partly hollow 56, pronouncedly 
hollow 66. 

Counts were made in order to determine whether certain plants 
produced fruits that were all hollow and other plants produced 
normal fruit. It appears that a single plant may produce both 
normal and hollow fruit. There is no stage in the life history of the 
tomato at which puffiness is a natural occurrence, but it may occur 
on small as well as large fruit. It does not seem to affect the amount 
of color or the time of ripening. Table X shows that although there 
are some differences in chemical composition between normal and 
"puffy" fruit there are no possible explanations to be gained from this 
standpoint. 

Various fertilizer plats were arranged to determine the effect of 
different amounts of nitrogen, potash, and phosphoric acid upon the 
production of "puffy" fruit. Seven plats were set out and the fertilizer 
mixtures were given in four applications at the rate of 1 ton to the 
acre. The fertilizer ingredients consisted of acid phosphate, sodium 
nitrate, and potassium sulphate, and the following ratios were used 
on the various plats: 1 : 5 : 3; 1 : 10 : 8; 3 : 5 : 3; 3 : 10 : 8; 3 : 6 : 0; 
7:5:3; and 7 : 10 : 8. 



Table X.— Composition of normal and "puffy'' Livingston Globe tomatoes, 
samples picked green, but fairly mature. 



Both 



Constituents. 


Normal fruit. 


"Puffy 


" fruit. 


Wet basis. 


Dry basis. 


Wet basis. 


Dry basis. 




94.3(3 
5.04 
2.93 

.140 
2.71 
2.40 
.42 
.034 
.190 
.55 

3.904 

2.71 

1.19 




94.32 
5.68 
2.84 
.139 
2.84 
2. til 
.38 
.033 
.197 
.54 

3.990 

2.84 
1. 15 




Total solids 




> 


Sugar-l'ree solids 


51.95 

2.48 

48.05 

42.55 

7.44 

.602 

3.54 

9.75 

69. 38 
48. 55 
20.83 


50.00 


Total nitrogen 


2.45 


Total sugar (as invert) 


50.00 




45. 95 


Starch 


6. 70 




.581 




3.47 


Crude fiber 


9.51 


Carbohydrates: 

Total 


70.26 


Soluble 


50.00 




20.26 







37 



38 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 

Examination of the fruit produced in this experiment showed that 
both normal and hollow fruits were to be found on every plat. Com- 
plete counts could not be made, owing to the destruction of the 
vines by a flood before the end of the season, but enough observa- 
tions were made to show that within the limits used varying quantities 
of fertilizer elements did not influence the production of hollow fruit. 

No positive results were obtained in this study showing the cause 
of puffiness in tomatoes, but the evidence indicated that the con- 
dition is not correlated with any considerable differences in the 
chemical composition of the mature fruit. The phenomenon is 
probably physiological in its nature, for the same varieties which 
show it in Florida are said not to do so, or only to a very slight extent, 
when grown in Michigan. A great difference that immediately 
occurs to one between conditions in the. two places is that in Florida 
the crop is produced only through heavy annual applications of 
commercial fertilizers, which are not used in Michigan. Puffiness 
may therefore be dependent upon an unbalanced soil solution, but, 
if so, none of the variations in the fertilizers just enumerated sufficed 
to restore a proper condition. It is, of course, not inconceivable that 
puffiness is of a genetical nature and due to somatic variation. If so, it 
might, in conformity with the observed facts, be much more frequent 
in some varieties than in others, and the same plant might show both 
normal and "puffy" fruit. The whole subject is one which needs 
investigation. 



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